本篇論文旨在設計一個內建三位元調光控制器之白光二極體背光驅動電路,即利用電壓模式脈波寬度調變控制架構,來有效控制功率元件的導通週期,以完成直流對直流升壓式轉換功能;另外,本篇論文也利用三位元的數位類比轉換器與斜波振盪產生電路,經由電壓比較器產生八種不同的脈波寬度訊號,用以調節白光二極體上所流過的電流導通週期,藉此來完成具有三位元調光功能的控制器。 本篇論文之晶片設計採用TSMC 0.35 μm 2P4M互補金氧半混合信號製程所完成,其晶片面積為1.45×1.28 mm2。當輸入電壓為3.7 V時,其輸出電壓為20 V且輸出電流為20 mA,可以驅動5顆3.5 V(20 mA)的白光二極體;透過調光控制器,可依不同的狀況調整白光二極體上的電流導通週期以及亮度。
This thesis focuses on the design of the white LED backlight driver with 3-bit dimming controller. By using the voltage-mode pulse width modulation, the power MOS duty cycle can be modified and the switching DC-DC boost converter can be implemented. Furthermore, a 3-bit digital-to-analog converter, a ramp and oscillator generator are needed to generate eight pulse-width signals through a voltage comparator. Thus, a 3-bit dimming controller can be implemented with the duty cycle of current for white LEDs. In this thesis, the proposed chip is designed and implemented with TSMC 0.35 μm 2P4M CMOS process. The simulation results of the switching DC-DC boost converter show that the input voltage, chip area, output voltage, and output current are 3.7 V, 1.45 ´ 1.28 mm2, 20 V, and 20 mA, respectively. This output voltage can drive five white LEDs with driving voltage of 3.5 V and driving current of 20 mA; the duty cycle and the brightness of white LEDs can be adjusted through the proposed dimming controller.